You can't just get the class 1 and import all you want, you have to have a demonstration cause. Vickers was using the demonstration letter to aquire guns for personal use via a police department that didn't have a reasonable need for the firearms and never actually had the guns demonstrated.
If you had a demonstration letter from Houston PD and, with your class 1, you imported an MP7 which representatives from Houston PD tried out under your supervision, that is above board. It wouldn't matter if they ended up buying MP7s or not.
If nobody from Houston PD ever saw the MP7 and that wasn't due to reasonable circumstances, that is questionable.
If you bought dozens of machines guns of various designs and the local police department wrote the letter as a favor with no intention of testing the guns, you are Vickers.
If you could just get a class 1 and go out and buy all the new machine guns you wanted, everybody would be buying machine guns.